We discuss the impact of strong absorption for thermal neutrons on data analysis and compare absorption corrections in the GSAS and MAUD Rietveld codes for texture and structural parameter refinement. Diffraction data were collected on the neutron powder diffractometer HIPPO at LANSCE from dysprosium and erbium, which are moderate to strong absorbers for thermal neutrons with absorption cross-s...

Conventional acoustical methods for measuring the permeability or flow resistivity of a porous material require a priori estimation of the porosity. In this work, an acoustical method is presented in which a simplified expression (independent of both the frequency and porosity) for the transmitted waves at the Darcy's regime (low frequency range) is derived, and used for the inverse determinati...

This paper is an overview of quasistatic measurement technique used to determine mechanical properties of sound absorbing materials. Experimental context and behaviour of polymer foam and rock wool are summarized. Concerning parameters are: static and dynamic strains, dynamic effects such as skeleton resonance and coupling with saturating fluid. Material anisotropy and frequency dependance of c...

Strong absorption of sound is often caused by the conversion of sound energy into heat. When this happens, it is not possible to study the interaction of sound with the absorbing material by means of reflected sound characteristics, because there is no reflected sound. Detecting for example the distance that sound travels in a strongly absorbing material, can be done by heat detection systems. ...

In this paper a review of impact mechanics and high-energy absorbing materials is presented. We review different theoretical models (rigid-body dynamics, elastic, shock, and plastic wave propagation, and nonclassical or nonlocal models. and computational methods (finite-element, finite-difference, and mesh-free methods. used in impact mechanics. Some recent developments in numerical simulation ...

Results from a numerical study examining micro-/macrorelations linking local geometry parameters to sound absorption properties are presented. For a hexagonal structure of solid fibers, the porosity phi, the thermal characteristic length Lambda('), the static viscous permeability k(0), the tortuosity alpha(infinity), the viscous characteristic length Lambda, and the sound absorption coefficient...